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Thread: Can CYA disappear with rain water?

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    TizMe's Avatar
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    Can CYA disappear with rain water?

    My pool was balanced a few weeks ago and with all the rain we have been getting here in Ga I have neglected testing my water because it was always raining when it was time to test. Since this is the first weekend we have had with no rain I decided to go see how out of balance my water was. I have had the solar blanket on to try to keep some of the junk out of the water.

    My CYA test tonight was 0 but three weeks ago it was 35 or so. Is it possible that all the rain has diluted my water that much? I did the test twice and got the same result.
    Les
    Don't have a pool right now. Just sharing what I have learned over the years!
    Helpful Links:
    Pool School,Pool Calculator,Cl/CYA Shock Chart,TF Test Kit
    Doing BBB and loving it!

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    Re: Can CYA disappear with rain water?

    It is extremely unlikely for a single rainfall to dilute the water enough to have the CYA drop by as much as you are seeing.

    What were the Free Chlorine (FC) and Combined Chlorine (CC) readings when you found that the CYA was zero. Also, by zero, do you mean that the pool water mixed with the CYA test reagent was completely clear or that filling up to the top was a little cloudy but the black dot was still visible? Does your CYA test as low as 30 ppm (as with the Taylor K-2006) or as low as 20 ppm (as with the TF100 from tftestkits.net)?
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    TizMe's Avatar
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    Re: Can CYA disappear with rain water?

    I have the TF 100 test kit and I could see the dot all the way to the top of the tube. My FC was 0 and I couldnt get any CC level when I tested for it. The water is green, but I took the solar cover off at night so just how green I cant tell but I cant see the bottom.The pool water was mixed with the CYA test reagent and I fille the tube to the top and the black dot was still visible. Last time I tested my CYA was after adding 32 oz in April and it was at 30ppm and the dot disappeared.
    This rain has been over the past 3 weeks or so. We have had lots of it here in Ga. I have drained water from the pool several times 4-5 inches or more at a time to keep it from over flowing the top rail.
    Les
    Don't have a pool right now. Just sharing what I have learned over the years!
    Helpful Links:
    Pool School,Pool Calculator,Cl/CYA Shock Chart,TF Test Kit
    Doing BBB and loving it!

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    Re: Can CYA disappear with rain water?

    It is possble that you have diluted your water enough to lower the CYA below 20 ppm with a starting point of only about 35 ppm

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    TizMe's Avatar
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    Re: Can CYA disappear with rain water?

    Ok, just wanted to make sure before I added more CYA to the pool ...
    Les
    Don't have a pool right now. Just sharing what I have learned over the years!
    Helpful Links:
    Pool School,Pool Calculator,Cl/CYA Shock Chart,TF Test Kit
    Doing BBB and loving it!

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    Re: Can CYA disappear with rain water?

    Since your FC is apparently 0 and your water is green, the CYA could also have been converted to ammonia by bacteria. If this happened, you could have a very high chlorine demand before you start reading FC. See what happens when you add chlorine to the pool. If it doesn't seem to be holding chlorine at all, then keep adding it until it does. In the worst case, if all the CYA got converted it could take almost 90 ppm FC cumulative to get rid of the ammonia, but I'll bet the algae consumed a lot of the ammonia so if you can filter some of it out then it will take a lot less chlorine to clear the pool.

    I hope waterbear is right and that you just diluted the pool down to where the CYA won't show up in the test (at least not to 20 ppm). It'll be a lot easier to handle if that's all that happened.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    frustratedpoolmom's Avatar
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    Re: Can CYA disappear with rain water?

    I'm hoping you still have a little in there too....and that it's not ammonia.

    Same thing's been happening to me - I'd say I've drained a foot of water this spring and it rained another 4 inches last week. I just added CYA to raise it to 50 and I don't want to drain more out.

    I'm kicking myself because I added tap water upon opening, paid $124 for the extra water, and I could have gotten it for free if I had waited a couple weeks.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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    TizMe's Avatar
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    Re: Can CYA disappear with rain water?

    I hear you FPM !!

    I am adding CYA this morning so we shall see what happens.
    Les
    Don't have a pool right now. Just sharing what I have learned over the years!
    Helpful Links:
    Pool School,Pool Calculator,Cl/CYA Shock Chart,TF Test Kit
    Doing BBB and loving it!

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